Abstract: A method, apparatus, and system for displaying widescreen video images on a stand video display is disclosed. Letterboxing, which occurs when a widescreen image is displayed in its entirety on a standard video display, is removed by enlarging the widescreen image and panning the enlarged widescreen image responsive to a multi-channel audio signal corresponding to the widescreen image.

Abstract: A method, apparatus, and system for displaying widescreen video images on a stand video display is disclosed. Letterboxing, which occurs when a widescreen image is displayed in its entirety on a standard video display, is removed by enlarging the widescreen image and panning the enlarged widescreen image responsive to a multi-channel audio signal corresponding to the widescreen image.

Abstract: A method, apparatus, and system for reducing cross-color distortion in an image produced by a composite video signal decoder is disclosed. Cross-color distortion, which is due to high frequency luminance being passed through the chrominance signal, is reduced by processing chrominance phases (i.e., color information) associated with a reference pixel and pixels adjacent the reference pixel to derive a scaling factor for scaling the reference pixel. The reference pixel is attenuated by the scaling factor if none of the adjacent pixels have a chrominance phase that is similar to the reference pixel.

Abstract: A method, apparatus, and system for reducing chrominance artifacts in a luminance signal obtained from a composite NTSC television signal is disclosed. Chrominance artifacts are reduced by detecting chrominance artifacts in the luminance signal of a current line and a previous line, weighting the luminance signal of the current line and the luminance signal of the previous line based on the detected chrominance artifacts, and combining the weighted luminance signal of the current line and the weighted luminance signal of the previous line for use as the luminance signal for the current line. Reducing chrominance artifacts reduces the occurrence of “hanging-dots” displayed on a television monitor, which are due to incompletely canceled chrominance artifacts in the luminance signal.

Abstract: Progressive-scan video signals that are generated from interlaced-scan video signals by interpolation may be subject to temporal distortion when the interstitial interpolated lines have a different time reference than the interlaced lines. This distortion may be mitigated by detecting vertical low-frequency spatial distortion in an interpolated video signal and by generating a compensating signal that, when added to the interpolated video signal reduces that vertical low-frequency spatial distortion. A spatial low-pass filter is applied to corresponding pixels of several adjacent lines of the current field of the original interlaced image. Concurrently, a spatial low-pass filter is applied to corresponding pixels of several interpolated lines that are inserted between the lines of the interlaced image to produce the progressive image. At each pixel position, the low-pass filtered values are compared.

Abstract: A motion estimation system for finding motion vectors between first and second images selects first and second overlapping blocks of pixels from the first image. The motion estimation system then estimates motion between the first and second images to define respective motion vectors for the overlapping blocks. These motion vectors are assigned to respective first and second non-overlapping sub-blocks of pixels within the respective first and second overlapping blocks of pixels. The motion estimation system is advantageously used in a video de-interlacing system in which the sub-blocks are used to determine whether interpolated samples are generated using samples from both the first and second image fields or only from the first field.

Abstract: A system for detecting and measuring registration errors and chromatic aberration in color images derived from a color video camera includes an edge locator which finds edges in respective zones of the color images and stores sets of samples representing picture elements of each of at least two component color signals. A microprocessor processes the stored sample sets to identify a coarse displacement between corresponding samples of the two component color signals. The microprocessor then determines a fine displacement between the two color signals. The coarse displacement may be determined by performing a cross correlation on the two sample sets or by calculating respective sums of absolute difference between the two sample sets for different displacements between corresponding samples of the two samples sets.

Abstract: Horizontal and vertical registration errors in a color television camera are automatically error corrected by detecting registration errors in live scenes. Each error is associated with the preselected region of the raster in which it was detected. The errors are separately collected for each region. An error waveform is generated from collected error values. The past history of registration errors is also used. A correction waveform is generated to correct the registration error by minimizing the error waveform. This automatic registration system is microprocessor controlled.

Abstract: An analog to digital converter which includes a resistive network for generating a number of first reference voltages related to each other by a first linear relationship and a number of second reference voltages related to each other by a second linear relationship, where the first linear relationship is different from the second linear relationship. Also included are first comparators which compare an analog signal to each one of the first reference voltages to produce specified first comparator signals where a respective comparator of the first comparators is provided for each of the first reference voltages. Second comparators are provided to compare the analog signal to each of the second reference voltages to produce second comparator signals where a respective comparator of the second comparators is provided for each one of the second reference voltages.

Abstract: A technique is disclosed for correcting black shading errors in a video camera. The technique involves calculating a horizontal correction waveform as a function of the average pixel values for the columns of a field. Next, a vertical correction waveform is calculated as a function of the average pixel values for the rows of a field. Then, calculation of a diagonal correction waveform as a function of the average pixel values along predetermined diagonals is performed. Finally, an input video signal representing real images is combined with the correction waveforms to produce a video output signal having substantially reduced black shading errors. Correction waveforms can be determined in any order.

Abstract: An apparatus is provided for processing the output signals of a charge transfer device having at least one row of photoelectric elements. The charge transfer device produces output signals with charge levels that are provided to a shift register having a plurality of elements. The successive charge levels from each photoelectric element are provided to respective shift register elements, and the charge levels are transferred within the shift register to a readout terminal. Some of the charge is retained by each element as the charge is transferred. The retained charge is added to the next charge transferred into the element. This adding of residual charges averages the charges transferred, producing undesirable noise. A sample and hold device removes sampling artifacts inherent in the signal provided by the CCD, to produce a signal representing successive image pixel values.

Abstract: A color video camera includes circuitry which generates a peaking signal that is applied to each of the color signals to enhance high-frequency components of the video signal relative to low-frequency components. The circuitry adds high-frequency components from the green video signal, as the peaking signal, at instants when the amplitudes of the green and red color signals are approximately equal. If there is a significant difference between the amplitudes of the red and green video signals, however, a combination of the high frequency components of both of these signals is used as the peaking signal. In one exemplary embodiment of the invention, the peaking signal includes in-band horizontal and vertical contour signals and out-of-band aperture correction signal.

Abstract: A method and apparatus for reducing the maximum gain applied to a video signal during gamma correction are disclosed. A gamma exponent value, a black level, white level, and a desired maximum gain value are selected. A count of possible input signal values is determined. A modified black level is set equal to the desired black level. A gain limit value for the gamma correcting transfer function is calculated, and the smallest input signal for which the applied gain is less than or equal to the gain limit is determined. A black level correction factor is calculated. The modified black level is increased by the black level correction factor, and a determination is made whether the black level correction factor has decreased to less than a predetermined threshold value. The gamma correction function is recalculated and further black level corrections are added until the correction threshold is reached.

Abstract: A method and apparatus for non-linear quantization of a signal that utilizes two or more lowresolution analog to digital converters (ADCs) to allow selective increased quantization levels at desired portions of a signal. This is accomplished by using a primary ADC which provides digital output signals over a first predetermined range, and at least one secondary ADC which provides digital output signals over a smaller predetermined range for the same input values. Accordingly, any secondary ADCs have a smaller quantization step size than the first, and are utilized when finer resolution is desired. The ADCs are kept in alignment by periodically comparing the digital values produced by the ADCs for a known input analog value.

Abstract: A method and apparatus for deriving a motion aperture signal that is added to a video signal to cause amplification of the high frequencies of the video signal during movement is disclosed. This method and apparatus operates with an interlaced scan television system by line interpolation of the fields adjacent to a present field of interest. One suggested interpolation means uses delay lines working in conjunction with a summer to vertically align adjacent fields with the field of interest. In order to match the amplitude response of the interpolation means operating on the adjacent fields and the amplitude response of the present field of interest, a filter is disclosed having the same delay line components as the interpolation means.

Abstract: A white shading correction system capable of automatic determination of the amount of white shading correction to be applied to specific video image pixels as well as the application of that correction to a digitized video signal is disclosed. This system includes an inspecting portion for identifying the required correction within a video frame, a calculating portion for computing the amount of correction to be applied to the video signal, and a correction portion for correcting the video signal based upon the correction computed by the calculating portion.

Abstract: A method and apparatus for gamma-correcting digital video data and for adjusting the video signal to a desired pedestal (black) level, gain (white) level, and a gamma correction value includes an apparatus for calculating digital values corresponding to a video signal having the desired gamma correction, black level and white level and a memory for storing the digital values. Uncorrected input digital video signals address the memory and cause the corresponding digital values stored in the memory, which represent the corrected video signal, to be output. The invention can be implemented in both software or hardware.

Abstract: Apparatus for translating a standard PAL composite signal into a composite signal in which the color signal is modulated on a subcarrier having an integral number of quarter cycles occurring during a line scanning interval. The standard PAL composite signal is written into a FIFO memory at 4.times.Fsc samples a second and read from the memory at 1135.times.Fh samples a second. Between fields the writing of the PAL composite signal is interrupted for two samples.

Abstract: Apparatus for decoding a luminance signal from a PAL composite signal comprising a summing one line delay for deriving the sum of corresponding pixels on adjacent lines of a field, a subtracting one line delay for driving the difference between pixels respectively adjacent to said pixels occur in another frame, an inverter for inverting the polarity of the output of said subtracting one line delay at twice the frequency of the color subcarrier, an adder coupled to said summing one line delay and to said subtractor, a two line delay coupled to the latter adder and another adder coupled to the opposite ends of said two line delay.

Abstract: Keying signals indicating locations along the lines of a raster where artifacts resulting from combing a video signal occur is derived by a one line subtractive filter, a clipping circuit and a one line AND device and means are provided for replacing video signals in said location with artifact free signals at the same location in either adjacent line if such are available and providing a signal that can be used to set up notch filter rather than combed operation if the corresponding locations on both adjacent lines also contain artifacts.